PEOPLE! STOP PANICING! Threre are hundreds of thousands of people like me who had Apple ID accounts for years and then one day decided to sign up for MobileMe with a MobileMe email address and have different Apple ID and mobile me accounts. Apple knows this and will come up with a solution. Apple is not gonna let people lose all their purchases. Get real people. It was just announced yesterday and still has months to go before going live. JUST HANG ON A BIT! SHEESH!
Now that I've thought about it a bit I agree. It'd be so outlandish of them to force people who paid for both iTunes purchases and .me email addresses choose between the two when iCloud comes out of beta. I know MM wasn't the most successful venture by them but they still had enough people sign up in order to make this a widespread issue.
The thing is, most MM users were already the hardcore Mac users to begin with. Why they thought these people wouldn't already have iTunes Apple ID's in the first place, and therefore decided make new iTunes Apple ID's with new MM accounts, is beyond me.
In any event I still think it's a good idea for us all to send feedback to Apple, just in case.